A history of acute weakness in the lower extremities is significant. This is an emergency and the patient should immediately be referred to a hospital.
Compression of lumbar nerve roots and cauda equina
Especially in a young patient, the main symptom is back pain radiating down the leg. This condition is not called gait dysfunction, but sciatica.
Difficulty in walking is a description used by the elderly, in whom the symptoms of chronic stenosis of the lumbar spine have become acute.
Cases where the condition is accompanied by sphincter dysfunction and sensory deficits in the buttocks, i.e. cauda equina syndrome, are emergencies and the patient should immediately be referred to a hospital.
Symptoms include weakness of the lower extremities, confusion, impaired or fluctuating consciousness, and possible signs of increased intracranial pressure or mild hemiparesis.
The history may include (even a slight) head injury.
Risk groups: the elderly, alcoholics, and patients receiving anticoagulant medication.
Multiple lacunar infarcts or vascular (frontobasal) degeneration in the brain
Among the most common causes of a slowly or gradually developing gait abnormality in the elderly.
Apraxic gait (the feet are strong enough, but the patient is unable to take any steps or the steps are short; legs are "glued to the floor") is a typical presentation.
Rarely diagnosed on the basis of gait disturbance, because the symptom does not develop until a later stage in the disease, although the patient's steps may become shorter also in the beginning of the disease.
Causes increasing weakness in the lower limbs accompanied by sensory disturbances within a few days, and later on also upper extremity symptoms. Tendon reflexes are decreased or absent.
A spinal inflammatory focus causes lower extremity weakness and sensory loss developing within a few days. The presentation often includes sphincter dysfunction.
Symptoms usually develop slowly. Both muscle weakness in the lower extremities and a stocking type sensory loss are in most cases present. Reflexes are attenuated or absent.
Several other neurological disorders (brain or spinal canal tumour, slow infection, myopathy, ALS, cerebellar diseases, etc.) may cause gait disturbance. Whenever the cause of the deteriorated ability to walk is unclear, neurological examination should be considered.
References
Giladi N, Horak FB, Hausdorff JM. Classification of gait disturbances: distinguishing between continuous and episodic changes. Mov Disord 2013;28(11):1469-73. [PubMed]
John G. Nutt. Higher-level gait disorders: An open frontier. Mov Disord 2013 Sep 15;28(11):1560-5.